Re: oversize motor?
When I purchased my toon, it was rated at 115hp max, but I knew it could take more since it was a tri-toon, so when I called the manufacturer they said I was correct and they sent me a new tag. With this said, I have been boarded several times for fishing and never once did they look at my engine rating.
Now, a over powered boat is dangerous, but 20hps is not a lot too me for such a large toon. I would definitely contact your manufacturer, I have found mine always happy to assist.